3 research outputs found
Reálná molekulární vizualizace v hodinách fyziky a chemie na základních a středních školách
The present article describes the potential use of molecular projection in chemistry and physics lessons. Beginnig of the text we point to the students´ Spatial imagination of students and the advantages of the real and computer molecular projection are discussed. Practical experience, ideas for work with molecular construction sets and several worksheets for students are added. © 2014, Czech Society of Chemical Engineering. All rights reserved
Remarks on restrained domination and total restrained domination in graphs
The restrained domination number γ r(G) and the total restrained domination number γ t r (G) of a graph G were introduced recently by various authors as certain variants of the domination number γ(G) of (G). A well-known numerical invariant of a graph is the domatic number d(G) which is in a certain way related (and may be called dual) to γ(G). The paper tries to define analogous concepts also for the restrained domination and the total restrained domination and discusses the sense of such new definitions. © Mathematical Institute, Academy of Sciences of Czech Republic 2005